Auditory trace fear conditioning requires animals to associate a tone conditioned stimulus and ia shock unconditioned stimulus that are separated by an empty 20-second trace interval. This learning task is dependent upon both the hippocampus and the amygdala, which are two of the most important structures in learning and memory. These structures have been studied extensively, but relatively few studies have examined how the hippocampus and amygdala interact. Recently, a process known as reconsolidation has been described where established memories can be lost if protein synthesis is inhibited immediately after the memory is recalled. It is not known, however, whether simultaneously acquired memories are recalled independently of one another or if the recall of one memory reactivates multiple related memories. Understanding how multiple memories are recalled and reconsolidated would provide insights into how neurodegenerative processes, such as natural aging and Alzheimer's disease, could disrupt established memories. This proposal will examine the roles of the hippocampus and amygdala in the consolidation of trace and contextual fear memories and determine if these simultaneously acquired memories can be recalled and disrupted independently of one another. This proposal will also determine if these two important structures have differential roles in encoding information about trace fear conditioning.